The present invention relates to torque rods and is more particularly directed to the bar or straddle pin component of a torque rod of the type commonly used in vehicle reaction rod units and the like.
Typically, prior art bar or straddle pins in torque rods have been made of solid metal such as steel. These bars are forged or machined from larger pieces of solid metal stock to the dimensions required for torque rod assembly. Tab ends, which are flat surfaces on the ends of the bar used for external connection purposes, are often machined. During the machining of these tab ends, stress riser grooves, cuts, etc. can occur, thus creating stress propagation points which tend to weaken the bar's overall structure and therefore reduce its reliability. In addition, the machining is an expensive and time consuming operation.
Another problem with the prior art bar pins is the high wear factor between the solid metal bar pin and the rubber bushing member of the torque rod. This high wear results from slippage between the bar pin and the rubber bushing as a result of time and normal use and the fact tht the metal bar pin surface is abrasive in nature. This abrasive wear problem is even more accentuated when corrosion occurs on the surface of the bar pin as is typical in the environment in which a torque rod is used.
Still another problem with metal bar pins is their weight. The use of the solid metal bar pin contributes to a high overall weight of the torque rod and in turn a higher total vehicle weight for any vehicle using such a torque rod. This increased weight of the torque rod will increase the energy requirements of the vehicle.